It is about the usage of 'just'. So while in the first case people think the just is justified, the before mentioned data indicates that only a few people manage to 'just' do it. The order of percentage of ppl beeing able to do it is the same as something which seems very hard to do (the everest thing). So while objectively they are comparable it shines light on that the usage of 'just' is bad in both cases while the subjective perception is very different. Not sure if I can make it clearer.

Edit:maybe I was thinking to complicated in this reply. The analogy is: you have two different things which can be achieved through doing a specific thing, but doing this thing is hard in both cases so using the word 'just' is not appropriate which is easier to see in the example.